Targeting the Protein-Membrane Interface Enables Design of Long-Acting CFTR Potentiators.

Area of Science:

• Biochemistry
• Molecular Pharmacology
• Membrane Protein Dynamics

Background:

• Therapeutically relevant membrane proteins often have druggable sites at the lipid-protein interface.
• Principles for designing ligands targeting these membrane-associated sites are not well-established.
• Cystic Fibrosis Transmembrane conductance Regulator (CFTR) potentiators serve as a model for membrane-targeted drug design.

Purpose of the Study:

• To explore structure-function relationships for designing ligands that stably engage lipid-exposed binding sites on membrane proteins.
• To identify modifications to the CFTR potentiator ABBV-974 that enhance its functional residence time.
• To establish generalizable strategies for developing drugs targeting membrane proteins.

Main Methods:

• Systematic modification of the lipophilic substituent of the CFTR potentiator ABBV-974.
• Measurement of functional residence time using patch-clamp assays and analysis of current decay after compound washout.
• Kinetic analysis correlating physicochemical properties of substituents with functional data.
• Molecular dynamics simulations to qualitatively assess ligand-protein interactions within the membrane.

Main Results:

• An analog of ABBV-974 with a modified lipophilic substituent demonstrated significantly increased functional residence time.
• Delayed current decay post-washout indicated prolonged channel potentiation.
• Kinetic analysis suggested increased residence time in the cell membrane contributed to enhanced kinetic stability.
• Molecular dynamics simulations provided qualitative support for increased membrane residence time.

Conclusions:

• Established a structure-function link between modifications to membrane-facing ligand portions and target engagement.
• Demonstrated that lipophilic substituent modifications can enhance the kinetic stability of CFTR potentiators.
• Proposed generalizable strategies for designing molecules with improved stability at lipid-exposed binding sites on membrane proteins.